42 CFR 410.12 – Medical and other health services: Basic conditions and limitations
(a) Basic conditions. The medical and other health services specified in § 410.10 are covered by Medicare Part B only if they are not excluded under subpart A of part 411 of this chapter, and if they meet the following conditions:
(1) When the services must be furnished. The services must be furnished while the individual is in a period of entitlement. (The rules on entitlement are set forth in part 406 of this chapter.)
(2) By whom the services must be furnished. The services must be furnished by a facility or other entity as specified in §§ 410.14 through 410.69.
(3) Physician certification and recertification requirements. If the services are subject to physician certification requirements, they must be certified as being medically necessary, and as meeting other applicable requirements, in accordance with subpart B of part 424 of this chapter.
(b) Limitations on payment. Payment for medical and other health services is subject to limitations on the amounts of payment as specified in §§ 410.152 and 410.155 and to the annual and blood deductibles as set forth in §§ 410.160 and 410.161.